Terence probably would know Astoria well, since I've worked out with Hermeh that he and Daphne are closely acquainted. However, his relationship with Daphne is antagonistic at best, so even if he's nice to Astoria, he's not all that nice to her sister. Just because he's a jerk. He's never violent around either of them, but he's not nice. xP
Christian fixes the magical cars that drive people around Muggleville. xD So it's a pretty low job in the ministry and he's often pretty dirty and such. Probably not the type Astoria would like to talk to. (But he's SPOCK... only not in icons here. He's more Sylar). I'm sure we could have them interact once or twice here and there! Just because he's around.